Expansible cutter tool



UUGI bij UUi'H L A n m H C T A L C m M w J.

L 0 O T R E T T U C E L B I s N A P x E Filed NOV. 30, 1936 l, Il.. n

INVENTOR; my am@ @up Patented May 10, 1938 UNITED STATES HULL! U11PATENT OFFICE EXPANSIBLE CUTTER TOOL John W. MacClatchie,

Los Angeles, Glenn D.

Application November 30, 1936, Serial No. 113,298

14 Claims.

This invention relates to expansible cutter tools and is particularlyapplicable to well drilling tools for enlarging the bore of a well, theinvention being illustrated and described in connection with that typeof tool wherein an expansible cutter scrapes the wall of the well bore.

It is an object of the invention to expand a cutter by relativelongitudinal movement of a mandrel, with a simple but eiiicientoperating connection between the mandrel and the cutter.

It is a further object of the invention to circulate a washing mediumthrough the bore of a hollow mandrel, with a port in the mandreldischarging a part of the washing medium at the cutter, and with saidport forming a part of the operating connection for expanding thecutter.

It is a still further object of the invention to utilize pressure of theWashing medium in the bore of the mandrel for expanding the cutter, byrestricting the bore of the mandrel by means of the contracted cutter sothat the pressure of the washing medium is directed against the cutterfor expanding the same.

It is a still further object of the inventionto actuate the mandrel bypressure of the washing medium, and to provide simple means forinitially restricting ow of the washing medium through the bore of themandrel so that the pressure of the flow is utilized for shifting themandrel, with this restriction subsequently removed so as to permit freecirculation of the washing medium.

It is a still further object of the invention to arrest operativemovement of the mandrel beiore the cutter reaches its fully expandedposition, with a lost motion operating connection permitting the cutterto then fully expand, and with said lost motion connection eliminatingwear at the operating connection when the cutter is expanded.

Further objects of the invention will be readily understood from thefollowing description of the accompanying drawing, in which:

Fig. 1 is a side elevation of the tool, partly in axial section andshowing its cutters contracted.

Fig. 2 is a similar View showing the cutters expanded.

Figs. 3 and 4 are transverse sections on the lines 3-3 and 4-4 of Figs.1 and 2 respectively.

The invention is illustrated in connection with an expansible cuttertool for scraping the wall of a well bore, and in the illustratedembodiment of the invention the tool has three cutters equidistantlycircumferentially spaced. The cutters are mounted on a body I which isadapted for incor- (Cl. Z55-76) poration in a usual drill string,preferably by means of a sub 2 which is threaded to the upper end of thebody I and which has a threaded connection 3 at its upper end, with thelower end of the body I also having a usual threaded connection (notshown). The cutters are mounted in radial slots 4 which are formed inthe body and which communicate with an axial bore 5 of the body. Amandrel 6 is slidable in the bore 5 and an operating connection isprovided between the mandrel and the cutters for expanding the latter.

The cutters are shown adapted for swinging movement to their expandedposition, and for this purpose cutters 'l may be pivoted on pins 8 whichextend across the slots 4 and which may be removably held in place asshown at 9. The cutters when contracted are contained within the slots 4as shown at Fig. 1, and when expanded swing outwardly and upwardly tothe position shown at Fig. 2, with their cutting edges la adapted toscrape the wall of a well bore when the tool is rotated.

The mandrel 6 is hollow, and the operating connection between themandrel and the cutters preferably includes a tubular extension 6a ofthe mandrel which is ported as shown at I for reception of lugs I Iwhich are preferably integral with the cutters 1. The tubular extension6a preferably has flattened surfaces I 2 alining with the respectivecutters, with the ports Ill formed in said flattened surfaces; and thelower end of the extension 6a may be of restricted diameter below theports I0 adapting said lower end of the extension for sliding receptionin the lower end of the bore which is preferably of restricted diameteras shown at 5a..

When the mandrel is elevated as shown at Fig. 1 the lugs I I arereceived in the ports I0 with the cutters l swung to contracted positionabutting the mandrel extension 6a. In this position the lugs II projectinto the bore of the tubular extension 6a so as to appreciably restrictsaid bore as shown at Fig. 3, and the lugs have surfaces I Ia. whichwhen the cutters are contracted taper downwardly as shown at Fig. 1,whereby downward pressure in the bore of the hollow mandrel is directedagainst the surfaces Ila so as to tend to swing the cutters l towardtheir operative position. The lugs Il also have surfaces IIU which whenthe cutters are contracted engage the upper ends of the ports I0, sothat downward movement of the mandrel shifts the lugs I I for swingingthe cutters toward their operative position.

The mandrel 6 may be shifted to expand the IlLIUIIl cutters by fluidpressure in the bore of the tool, and for this purpose the sub 2 mayhave a bore |50. which forms a cylinder I5 for a piston, with the boreof the sub open at its upper end for communication with the bore of thedrill string in which the tool is incorporated. The piston is xed to theupper end of the hollow mandrel for pressure responsive downwardmovement in the cylinder I5 so as to downwardly shift the mandrel, andin the illustrated embodiment of the invention the piston is shown asincluding an abutment I6 integral with the hollow mandrel 6, with apiston rubber I1 which preferably has a reinforcement plate I8, securedto the abutment I6 by means of a follower I9.

When the cutters 'I are contracted and the hollow mandrel 6 is elevatedas shown at Fig. l, a plug 20 which is supported by the sub 2 preferablyextends into the upper end of the bore of the hollow mandrel so as toappreciably restrict flow through said bore and thus maintainappreciably pressure against the piston I'I for depressing the mandreland thereby swinging the cutters toward their operative position; andthe restricted flow past the plug 20 and through the bore of the hollowmandrel exerts pressure against the surfaces II a of the lugs I I foraiding in swinging the cutters toward their operative position.

Downward movement of the mandrel 6 is preferably terminated by theabutment I6 engaging a cooperating abutment surface 22 at the upper endof the body I, and with the parts in this position the mandrel haspreferably not yet swung the cutters to fully expanded position. Howeverthe cutters are so nearly fully expanded as to engage the wall of thewell bore so that the weight of the drill string completes the swingingmovement of the cutters to their fully expanded position as determinedby abutment of their surfaces Ib against the upper ends of the slots 4.This nal swinging movement of the cutters after downward movement of themandrel has been arrested, spaces the lugs II from the upper ends of theports I0 as shown at Fig. 2. and as a result of this lost motionconnection the tool may be operated with its cutters expanded, with nowear between the lugs I I and the ends of the ports I0.

By the time downward movement of the mandrel 6 has been arrested itsbore will have shifted clear of the plug 20 as shown at Fig. 2, so thatthe entire flow through the drill string is then directed through thebore of the mandrel, and when the cutters have been fully expanded theirlugs II will have been swung clear of the bore of the mandrel so as tooffer no obstruction to this flow. Flow is thus directed through thehollow mandrel extension 6a and thence downwardly through the lowerportion of the bore 5 and through the bore of that portion of the drillstring which depends from the body I, so as to maintain usualcirculation through the drill string. At the same time the lugs II ofthe expanded cutters are swurg clear of the lower portions of the slotsI0 which are of such appreciable length that these unobstructed lowerportions of the slots form outlets of appreciable area through which anappreciable portion of the ow in the bore of the hollow mandrel isdirected laterally outwardly through the slots 4 and just below theexpanded cutters.

When the cutters are to be contracted the drill string is elevated, andas a result of binding engagement of the expanded cutters with the wallof the well bore the cutters are swung toward their contracted position.Further contraction of the cutters results if the drill string iswithdrawn through an upper portion of the well bore, such as a casingstring, which is of smaller diameter than that ldefined by the expandedcutters, and complete contraction of the cutters is preferably assuredby mounting a spring 3U in the bore 5 around the mandrel 6, between theabutment I6 and a supporting collar 3| which seats on a shoulder in saidbore. As soon as the force tending to hold the cutters in expandedposition is relieved by elevating the drill string, the spring 30 thustends to retract the mandrel 6 so that the lower ends of its ports IUengage the lugs I I for contracting the cutters.

The invention thus provides an arrangement whereby the ports I0cooperate with the lugs II for expanding and contracting the cutters,with said ports also serving as outlets for discharge of a washingmedium through the slots 4 and below the expanded cutters, and with saidports also permitting projection of the lugs II into the bore of thehollow mandrel when the cutters are contracted, so that flow through thehollow mandrel and directed against the lugs may aid in expanding thecutters.

In the claims, we have use-d the word body to include the body I and thesub 2, and similar structures.

We claim:

1. In an expansible cutter tool, a body having a radial slot, a hollowmandrel mounted in said body, said mandrel having a lateral portcommunicating with said radial slot, a cutter mounted in said radialslot having a projection cooperating with the port for shifting thecutter by movement of the mandrel, and means for directingva washingmedium through the hollow mandrel for discharge at the port.

2. In an expansible cutter tool, a body having a radial slot, a hollowmandrel mounted in said body, said mandrel having a lateral portcommunicating with said radial slot, a cutter mounted in said radialslot having a projection cooperating with the port for shifting thecutter by movement of the mandrel, and means for direct- 4 drel andagainst the projection for shifting the cutter. l,

4. In an expansible cutter tool, a hollow mand drel, a cutter having aprojection extending into the bore of the hollow mandrel, means forshifting the cutter by movement of the mandrel, and means for exertingpressure in the bore of the hollow mandrel and against the projectionfor aiding in shifting the cutter.

5. In an expansible cutter tool, a hollow mandrel, a cutter having aprojection extending into the bore of the hollow mandrel, means forshifting the cutter by movement of the mandrel, and means for directingpressure against the mandrel for moving the same, with said pressuredirected thence through the hollow mandrel and against the projectionfor aiding in shifting the cutter.

6. In an expansible cutter tool, a hollow mandrel having a lateral port,a cutter having a projection extending through the port and into thebore of the mandrel for shifting the cutter by ling a lateral port, anda projection on the cutter movement of the mandrel, and means whereby awashing medium may be directed against the mandrel for moving the same,with said washing medium/ directed thence through the hollow mandrel andagainst the projection for aiding in shifting the cutter and fordischarge through the port.

7. In an expansible cutter tool, a body, a hollow mandrel movable in thebody, a plug xed to the body and extending into the bore of the hollowmandrel when the mandrel is retracted and being clear of the bore of themandrel when the mandrel is projected, a cutter carried by the body, andmeans for moving the cutter by projection of the mandrel.

8. In an expansible cutter tool, a hollow mandrel having a lateral port,means for restricting the bore of the hollow mandrel when the mandrel isretracted and for'opening the bore of the hollow mandrel when themandrel is projected, and a cutter having a projection cooperating withthe port for shifting the cutter by projection of the mandrel.

9. In an expansible cutter tool, a mandrel, means for limiting movementof the mandrel, a cutter, and a lost motion connection for shifting thecutter by movement of the mandrel and permitting continued shifting ofthe cutter after movement of the mandrel has been stopped.

10. In an expansible cutter tool, a hollow mandrel having a lateralport, means for limiting movement of the mandrel, and a cutter having aprojection adapted for engagement by the wall of the port for shiftingthe cutter by movement of the mandrel and permitting continued shiftingof the cutter after movement of the mandrel has been stopped so as tospace the projection from said wall of the port.

l1. In an expansible cutter tool, a hollow body having a slot, a cutterin said slot, a hollow mandrel movable in the bore of the body andhavadapted for engagement by the wall of the port for expanding thecutter by movement of the mandrel.

12. In an expansible cutter tool, a hollow body r having a slot, acutter in said slot, a hollow mandrel movable in the bore of the bodyand having a lateral port, and a projection on the cutter adapted forengagement by the wall of the port for expanding the cutter by movementof the mandrel, the projection extending into the bore of the hollowmandrel when the cutter is contracted so that pressure directed throughthe bore of the hollow mandrel is exerted against the projection foraiding in expanding the cutter.

13. In an expansible cutter tool, a hollow body having a slot, a cutterin said slot, a hollow mandrel movable in the bore of the body andhaving a lateral port, a projection on the cutter adapted for engagementby the wall of the port for expanding the cutter by movement of themandrel, and means for limiting said movement of the mandrel, the portengaging the projection so as to permit continued expansion of thecutter after movement of the mandrel has been stopped, so as to spacethe projection from the said wall of the port.

14. In an expansible cutter tool, a hollow body having a slot, a cutterin said slot, a hollow mandrel movable in the bore of the body andhaving a lateral port, a projection on the cutter adapted for engagementby the wall of the port for expanding the cutter by movement of themandrel, and a plug fixed to the body so that it is received in the boreof the hollow mandrel when the mandrel is retracted but clears the boreof the hollow mandrel when the mandrel is projected.

JOHN W. MACCLATCHIE. GLENN D. JOHNSON. CARL A. THIES.

